sluitdiaphragma

Sluitdiaphragma, in English the diaphragma sellae, is a thin dural fold that forms the roof of the sella turcica, the saddle-shaped bony cavity in the sphenoid bone that houses the pituitary gland. It is part of the brain’s meninges and lies between the suprasellar region above and the pituitary gland within the sella.

Anatomy and attachments: The sluitdiaphragma is a circular or oval sheet of dura mater that wraps over the sella turcica, with its edges attaching to the margins and adjacent clinoid processes. It contains a small central opening through which the infundibulum (pituitary stalk) and accompanying vessels pass from the hypothalamus to the pituitary gland. The structure acts as a barrier between the intra-sellar space and the suprasellar cistern, where the optic apparatus and hypothalamic connections reside.

Function: The diaphragma sellae provides protective covering for the pituitary gland and helps separate the gland from higher brain structures. The opening for the infundibulum allows the neural and vascular connection between the hypothalamus and the pituitary to pass while maintaining a partial separation of compartments.

Clinical relevance: Pathological processes such as pituitary adenomas often extend upward into the suprasellar space, potentially compressing the optic chiasm and causing visual disturbances. Conditions like empty sella syndrome involve alterations of the diaphragma sellae and the surrounding CSF space. The diaphragma sellae is also considered in transsphenoidal surgical approaches to the pituitary.

Imaging: On MRI and CT, the sluitdiaphragma appears as a thin dome-shaped dural roof over the sella, with the infundibulum passing through its central aperture.